Fragmentation projectile



Sept. 19, 1961 L. ZAPF FRAGMENTATION PROJEMILE:v

Filed Jan. 30, 1943 nited States. Patent 3,000,309 FRAGMENTATION PROJECTILE Louis Zapf, Rockaway, N J., assignor to the United States of America as represented by the Secretary of War Filed `lan. 30, 1943, Ser. No. 474,197 6 Claims. (Cl. IGZ-67) (Granted under Title 35, U.S. yCode (1952), sec. 266) The inventio-n described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to a controlled fragment-ation shell or bomb.

It has been demonstrated that natural voids, indentations, or depressions, as well as voids made by design in high explosives will, upon detonation of the mass, be impressed or reproduced by the gases of the explosion upon tllre iron or steel surface against which the explosion takes p ace.

To utilize this principle, sometimes referred to as the Munroe Effect my idea is to place inside an explosive shell a charge-containing insert, parts of which will be flush against the inner wall of the shell, others being spaced from the wall, the voids and contacting surfaces being arranged in a pattern and size according to the fragmentation control desired, the object being to control with certainty the fragmentation of the shell.

The present practice is, where fragmentation control is desired, to serrate the interior of the shell, weakening it at points for the purpose.

According to the present invention no scoring, grooves or serrations of any kind are made in the interior wall of the shell, thus greatly lowering the cost of military ammunition of this character, and at the same time effecting a more certain control of the fragmentation.

The drawing illustrates a preferred pattern form of insert, but it should be understood at the outset that other forms may be employed, so long as the insert comprises portions substantially in contact with the inner wall of the shell, and other portions forming voids or spaces between the insert and the shell which in effect, due to the pattern of the insert, s a space or spaces between the charge and the shell.

In the drawings:

FIG. l is a longitudinal section of the shell and insert.

FIG. 2 is a cross section taken on the line 2 2 of FIG. l.

FIG. 3 is a similar view taken on the line 3-3 of FIG. l, and

FIG. 4 is a fragmentary longitudinal section taken about on the line 4 4 of FIG. l.

Reference being had to the drawings, the numeral 1, designates the projectile or shell having a smooth uninterrupted inner wall 2, the base of which shell may be closed by a disk or by any suitable or usual base closures, so long as the closure permits the entrance of the insert to the interior of the shell.

The numeral 4 indicates the insert generally tubular in form and adapted to receive the explosive charge, such for instance as TNT, and shaped so that when in place in the shell parts of its outer periphery will fit snugly against the inner wall of the shell, as shown, and other parts will be spaced therefrom.

Longitudinal grooves 5 and circumferential grooves 6,

Patented Sept. `1 9, 1961 2 are provided in the insert, the grooves being continuous yand intersecting and .forming substantially rectangular portions 7 between them. The portions 7 fit closely against the wall of the shell, whereas the V-shaped grooves form' voids between the insert and the shell and define the lines or patterns which fragmentation will fllow in the burst# ing of the shell.

The insert forms a matrix for the high explosive which ordinarily will be of the TNT type, melted and poured into the insert while the insert is in the shell, that is to say the shell with the contained insert is filled or loaded, `and the charge subsequently drilled for the booster charge, as usual.

Upon the explosion of the charge the insert will ordinarily be completely comminuted, and the forces` of the gases lgenerated by the explosion will be directed and localized along the lines defined by the voids, thus causing the fragmentation of the shell at these points.

As illustrated the size of the insert is commensurate with the inner wall of the projectile, but it may be made in sections or lengths shorter than the projectile, as in cases where i-t might be desirable to fragment less than the entire projectile.

I do not limit myself to the material of which the insert is made. It may be that heavy sized paper I have specified, although reinforced by the very hard TNT within the insert wi-ll not be sufficient to stand the set back in firing, in which event, obviously, strong material such as iron or steel or other suitable material may be employed, or instead of placing the insert in -the shell and afterward filling it with the explosive, I may dispense with the insert and precast the charge and thereafter insert it in the shell.

The invention is also useful in connection with grenades, with respect to which lammunition the shell setback need not be of great consideration.

I claim:

l. A projectile comprising a shell, an insert in said shell for reception of the explosive charge, and provided with longitudinal and circumferential intersecting grooves forming portions in contact with the inner wall of the shell and other portions out of contact to form voids or spaces between the charge and the shell, said portions in contact with the inner wall of said shell forming bases of voids and said other portions out of contact forming point terminations of said voids extending inwardly beyond the inner wall of said insert to direct the gases of the explosion -against the shell at predetermined points to control the pattern and extent of shell fragmentation.

2. The invention according to claim l, characterized in that the longitudinal and circumferential grooves are V-shape in cross-section.

3. The invention -according to claim 1, characterized in that the grooves are V-shape and continuous.

4. A projectile comprising -a metallic shell of generally uniform wall thickness, a rigid liner fitting within said shell and having its wall indented to form a plurality of parallel outwardly-opening grooves, V-shaped in cross section, and a mass of explosive Within said liner.

5. A projectile comprising a metallic shell having smooth walls of generally uniform thickness, a thinwalled rigid matrix fitting within said shell, said matrix having its walls formed with a plurality of channels V-shaped in cross-section, and a solid mass of explosive filling said matrix.

6. A projectile comprising a metallic shell having ly about and along said matrix, and a solid charge of 5 explosive conforming to the inner surface of said matrix.

References Cited in the file of this patent UNITED STATES PATENTS Re. 23,211 Mohaupt Mar. 21, 1950 34,798 Wickersham Mar. 25, 1862 47,651 Libbey May 9, 1865 4 726,901 Gathmann May 5, 1903 1,015,944 DuPont Jan. 30, 1912 FOREIGN PATENTS 133,076 Great Britain Oct. 9, 1919 847,066 France June 26, 1939 113,685 Australia Aug. 14, 1941 OTHER REFERENCES Voina i Tekhnika, vol. 253 (of 1926), pages 18-24 with 8 sheets of dwg. An article by Sukharevsky entitled Phenomena Produced by the Explosion of Hollow Cartridges and the Practical Importance of the Application of the Principle in Blasting Practice. 

